<?php
require_once(__DIR__ . "/errorCode.php");

/**
 * PKCS7Encoder class
 *
 * 提供基于PKCS7算法的加解密接口.
 */

class PKCS7Encoder
{
    public static $block_size = 16;

    /**
     * 对需要加密的明文进行填充补位
     * @param $text 需要进行填充补位操作的明文
     * @return 补齐明文字符串
     */

    public function encode($text)
    {
        $block_size = PKCS7Encoder::$block_size;
        $text_length = strlen($text);
        $amount_to_pad = PKCS7Encoder::$block_size - $text_length % PKCS7Encoder::$block_size;
        if( $amount_to_pad == 0 )
        {
            $amount_to_pad = PKCS7Encoder::$block_size;
        }

        $pad_chr = chr($amount_to_pad);
        $tmp = "";
        for( $index = 0; $index < $amount_to_pad; $index++ )
        {
            $tmp .= $pad_chr;
        }
        return $text . $tmp;
    }

    /**
     * 对解密后的明文进行补位删除
     * @param decrypted 解密后的明文
     * @return 删除填充补位后的明文
     */

    public function decode($text)
    {
        $pad = ord(substr($text, -1));
        if( $pad < 1 || 32 < $pad )
        {
            $pad = 0;
        }

        return substr($text, 0, strlen($text) - $pad);
    }

}


/**
 * Prpcrypt class
 *
 *
 */

class Prpcrypt
{
    public $key = NULL;

    public function __construct($k)
    {
        $this->key = $k;
    }

    /**
     * 对密文进行解密
     * @param string $aesCipher 需要解密的密文
     * @param string $aesIV 解密的初始向量
     * @return string 解密得到的明文
     */

    public function decrypt($aesCipher, $aesIV)
    {
        try {

            // $module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');

            // mcrypt_generic_init($module, $this->key, $aesIV);
            // //解密
            // $decrypted = mdecrypt_generic($module, $aesCipher);
            // mcrypt_generic_deinit($module);
            // mcrypt_module_close($module);
            $decrypted = openssl_decrypt($aesCipher,'AES-128-CBC',$this->key,OPENSSL_ZERO_PADDING,$aesIV);
            // var_dump($decrypted);
        } catch (Exception $e) {
            return array(ErrorCode::$IllegalBuffer, null);
        }
        try {
            //去除补位字符
            $pkc_encoder = new PKCS7Encoder;
            $result = $pkc_encoder->decode($decrypted);
        } catch (Exception $e) {
            //print $e;
            return array(ErrorCode::$IllegalBuffer, null);
        }
        return array(0, $result);
    }

}
?>
